Field of the Invention
The present invention is generally directed to the field of urology. More particularly, the present invention is directed to the field of male contraception. Even more particularly, the present invention is directed to methods and compositions for male contraception by way of percutaneous administration of one or more occlusive substance into the vas deferens. The methods are advantageously performed under the guidance of an imaging modality, such as ultrasound imaging, to ensure placement of the occlusive substance into the lumen of the vas deferens. Also disclosed are methods of reversal of the male contraception. Also disclosed are compositions of occlusive substances that are visible by way of ultrasound imaging and other types of imaging.
Description of Related Art
Vasectomy is a procedure for producing male contraception which involves severing the vas deferens. Potential complications of vasectomy include bleeding at the site of the surgical procedure, which may cause swelling or bruising; infection at the site of the incision; infection in the scrotum; sperm granuloma; congestive epididymitis; recanalization; and the inability to reverse the vasectomy. Additionally, a portion of patients report pain after the procedure. Possibly the largest deterring factor of vasectomy, besides the surgical nature of the procedure, is the difficulty of reversing the vasectomy. The procedure, known as vasovasostomy, is a three to four hour long, expensive microsurgical procedure in which the patient is under general anesthesia. Further, a vasovasostomy also does not guarantee the man restores his fertility due to the presence of anti-sperm antibodies that persist in the body after the vasovasostomy.
Due to these potential complications and difficulty in reversing the procedure, alternative procedures for long-lasting male contraception have been explored. One strategy that has been the subject of research and development is vas-occlusive contraception, which involves injecting or implanting a substance into the vas deferens lumen to occlude this vessel so that the flow of sperm cells from the epididymis is blocked. Particular examples include RISUG, which involves implantation of styrene maleic anhydride, VASALGEL, which involves implantation of styrene maleic acid, as well as polyurethane and silicone implants. However, technical barriers for successfully introducing these procedures into the male contraceptive armamentarium have been documented.
Examples of related efforts include those described in U.S. Pat. Nos. 5,488,075; 5,667,767; 6,103,254; 6,858,219; 6,756,031; 8,551,001; 8,123,693; 8,613,282; 8,689,792; 8,550,085; 8,434,489; 8,113,205 7,975,697; 7,694,683; 7,398,780; 7,073,504; 6,432,116; 6,096,052; 8,360,064; 9,034,053; 8,322,341; 8,235,047; 7,918,863; 7,694,683; 8,048,086; 9,220,880; 9,034,053; 8,726,906; 8,695,606; 8,336,552; 8,324,193; 8,316,854; 8,316,853; 8,052,669; 8,048,101; 8,048,086; 8,226,680; 7,789,891; 4,920,982; 8,603,080; 4,269,174; 6,485,426; 8,316,854; and 8,551,001; as well as U.S. Patent Application Publication Nos. 2005/0045183; 2015/0068531; 2015/0136144; 2008/0308110; 2005/0192616; 2010/0063392; and 2004/0240715. Additional related efforts include the following: Reddy, N. M., et al., J. Clin. Ultrasound, 32: 394-398 (2004); Abdala, N. et al., Journal of Vascular and Interventional Radiology, 12(8): 979-984 (2001); Zhao, S. C., Contraception, 41(5):453-459 (1990); Guha, S. K. et al., Contraception, 56:4, 245-250 (1997); Chaki, S. P. et al., Contraception, 67(1):73-78 (2003); Lohiya, N. K. et al., Contraception, 71(3):214-226 (2005); Liu, X. et al., Contraception, 56(6): 391-394 (1997) (“Liu, X. et al.”); Koul, V. et al., Contraception 58(4):227-31 (1998); Lohiya, N. K., et al., Indian J Med Res 140 (Supplement): 63-72 (2014); Roy, S. et al., Colloids and Surfaces B: Biointerfaces 69: 77-84 (2009); Zhao, S. C., International Journal of Andrology, 15:460-464 (1992); Soebadi, D. M., International Journal of Andrology, 18: 45-52 (1995); Jha, R. K., et al., International Journal of Nanomedicine, 4:55-64 (2009); Middleton, W. D., et al., J Ultrasound Med., 28(7):839-46 (2009); Naughton, C. K., et al., Journal of Andrology, 25: 545-553 (2004); Waller et al., Basic and Clinical Andrology, 26:6 (2016); and Zambon, J. V., BJU International, 86, 699-706 (2000). Yet, despite these efforts, there remains a need in the art for an improved method of male contraception that can be made available to men in need of a safe, effective, and easily administered reversible contraceptive.